[Intel-gfx] [PATCH] drm/core: Change declaration for gamma_set.

[Maarten Lankhorst]

Op 06-06-16 om 18:25 schreef Emil Velikov:
> On 6 June 2016 at 17:15, Maarten Lankhorst
> <maarten.lankhorst at linux.intel.com> wrote:
>> Op 06-06-16 om 18:11 schreef Emil Velikov:
>>> On 6 June 2016 at 17:00, Daniel Vetter <daniel at ffwll.ch> wrote:
>>>> On Mon, Jun 06, 2016 at 11:18:09AM +0200, Maarten Lankhorst wrote:
>>>>> Change return value to int to propagate errors from gamma_set,
>>>>> and remove start parameter. Updates always use the full size,
>>>>> and some drivers even ignore the start parameter altogether.
>>>> Commit message should explain why we suddenly need to pass up the error
>>>> code, too:
>>>>
>>>> "This is needed for atomic drivers, where an atomic commit can fail with
>>>> EAGAIN and should be restarted."
>>>>
>>> Since that can happen only on the DRM core side, shouldn't one refrain
>>> from adding the "always returns 0" return status for the drivers'
>>> .gamma_set hook ? Or there's is something in the works that would lead
>>> to drivers being able to return a non 0 value ?
>> Look at drm_atomic_helper.c :-)
>>
>> Being implemented as an atomic update means any errno can be returned.
>>
> Ouch. Looks like only the i915 driver uses the helper while I was
> looking at other ATOMIC drivers. So things short circuited on my
> noggin'. I guess it's up-to the respective drivers to be updated and
> use the drm_atomic_helper_legacy_gamma_set helper.
>
> Thanks for sticking with my silly question :-)
Feel free to convert some drivers over, would be nice to have more widespread support for changing gamma through atomic properties. :-)